Surface water drainage. Budgetary site drainage and storm sewer systems from portal users. Discharge of collected water

Built in accordance with all the rules, taking into account the characteristics of the soil and in compliance with construction technology, then only soil and ground moisture will pose a danger to its strength and durability. The integrity of the foundation of the house can be damaged by the influence of rain and melt water that enters the soil and does not have the possibility of timely care due to the seasonal rise in level groundwater, or if they pass close to the surface.

As a result of such waterlogging of the soil near the foundation, the parts of its structure become damp, and undesirable processes of corrosion and erosion may well begin in them. In addition, dampness is always a prerequisite for damage building structures fungus or other representatives of harmful microflora. Fungal colonies on the walls of premises they quickly take over territory, spoiling the finish and negatively affecting the health of the residents of the house.

These problems must be solved at the design and construction stage of the building. The main measures are the creation reliable waterproofing structural elements and properly organized drainage of water from the foundation of the house. About waterproofing - a special conversation, but the water drainage system requires careful calculations, selection of appropriate materials and components - fortunately, these days they are presented in a wide range in specialized stores.

The main methods of draining water from the foundation of a building

To protect the foundation of the house from atmospheric and ground moisture, they are used various designs, which are usually combined into one system. This includes blind areas around the perimeter of the house, storm drainage with the roof drainage system included in it, a complex of storm water inlets, horizontal drainage with a set of transport pipes, inspection and storage wells and collectors. To understand what these systems are, we can look at them in a little more detail.

Blind areas

The blind areas around the perimeter of the house can be called mandatory element for draining rain and melt water from the foundation. In combination with a roof drainage system, they are able to effectively protect the foundation of the house even without arranging a complex storm sewer, if the amount of seasonal precipitation in a given region is not critical, and groundwater runs deep from the surface.

Blind areas are made from different materials. As a rule, their placement is planned with a slope at an angle of 10–15 degrees from the wall of the house, so that water flows freely into the soil or storm drain gutters. The blind areas are located along the entire perimeter of the building, taking into account that they should have a width of 250÷300 mm larger than the protruding eaves or gable overhang of the roof. In addition to good waterproofing, the blind area also has the function of an external horizontal line for insulating the foundation.

Construction of blind areas - how to do it right?

If you do everything “in your mind”, then this is a very difficult task. It is necessary to thoroughly understand the design, to know which materials will be optimal for specific construction conditions. The process is outlined with all the necessary details in a special publication on our portal.

Storm sewer with drainage system

A drainage system is required for every building. Its absence or incorrect planning leads to the fact that melting and rainwater will fall on the walls, penetrate to the base of the house, gradually eroding the foundation.

Water from the drainage system should be directed as far as possible from the foundation of the house. For this purpose it is used whole line devices and elements of storm drainage systems of one type or another - storm water inlets, open gutters or pipes hidden under scrapped earth, sand traps, filters, inspection and storage wells, collectors, storage tanks and others.

Roof drainage system – we install it ourselves

Without properly organized collection of water from a considerable area of the roof, talking about effective drainage of water from the foundation is simply ridiculous. How to correctly calculate, choose and install on the roof - all this is described in a special publication on our portal.

Drainage wells

Drainage wells are usually used as independent, autonomous elements of a water drainage system when arranging bathhouses or summer kitchens, not connected to the domestic sewage system.

To build such a well, you can use a metal or plastic barrel with perforated walls. This container is installed in a pit dug for it, and then filled with crushed stone or broken stone. The drainage system of the bathhouse is connected to the well by a gutter or pipe, through which water will be drained from the foundation.

This system is obviously extremely imperfect, and in no case should it be combined with storm sewerage, since heavy rain a rapid overflow with a sewer overflow cannot be ruled out, which is certainly not very pleasant. However, under conditions country house construction they resort to it quite often.

Drainage system

Arranging a full-fledged drainage system in conjunction with storm sewerage is a very responsible and labor-intensive process that requires considerable material investments. However, in many cases it is impossible to do without it.

For this system to work effectively, it is necessary to carry out careful engineering calculations, which are most often entrusted to specialists.

Prices for storm drainage

storm drain

Since this is the most complex, but at the same time the most effective option for draining water from the base of a building, and can be performed in different ways, it needs to be considered in more detail.

Drainage system around the house

Is it always necessary to install a drainage system?

By and large, it is highly desirable that drainage be installed around any building. However, in some cases, a water drainage system is simply vital, since there are a number of objective reasons for this, which include:

Groundwater is located between layers of soil close to the surface.
There are very significant amplitudes of seasonal rises in groundwater.
The house is located in close proximity to a natural reservoir.
The construction site is dominated by clay or loamy soils, wetlands or peat bogs saturated with organic matter.
The site is located on a hilly area in a lowland area where melt or rainwater can obviously collect.

In some cases, you can refuse to arrange a drainage system, making do with blind areas and properly organized So, there is no urgent need for a full-fledged drainage circuit in the following situations:

The foundation of the building is erected on sandy, coarse or rocky soil.
Groundwater passes below floor level basement no less than 500 mm.
The house is installed on a hill where melt and rain water never collects.
The house is being built far from bodies of water.

This does not mean that such a system in these cases is not needed at all. It’s just that its scale and overall productivity may be smaller – but this should already be determined on the basis of special engineering calculations.

Types of drainage systems

There are several types of drainage systems that are designed to remove moisture of various natures. Therefore, the choice is made on the basis of geotechnical studies carried out in advance, which determine which options are most suitable for a particular site.

Drainage can be divided into the following types according to the area of application: internal, external and formation. Quite often all types of drainage are installed, for example, an internal drainage option is used to drain groundwater from the basement, and an external one for soil water.

Formative drainage is almost always used - it is installed under the entire structure and is a sand, crushed stone or gravel “cushion” different thicknesses, mostly 100÷120 mm. The use of such drainage is especially important if the groundwater is located high enough to the floor surface of the basement.

The external drainage system is installed at a certain depth or placed superficially along the walls of the building and on the site, and is a set of trenches or perforated pipes that are installed with a slope towards the drainage tank. Through these channels, water is drained into a drainage well.
Internal drainage is a system of perforated pipes that are laid under the floor of the basement of a house, and, if necessary, directly under the foundation of the entire house, and discharged into a drainage well.

External drainage system

The external drainage system is divided into open and closed.

The open part, in essence, is a system for collecting storm or melt water from the roof drainage system and from concreted, asphalted or lined paving slabs areas of the territory. The collection system can be linear - with extended surface trays, for example, along the outer line of blind areas or along the edges of paths and platforms, or point - with storm water inlets connected to each other and to wells (collectors) by a system of underground pipes.

A closed drainage system includes in its design perforated pipes buried in the ground to a depth determined by the design. Very often, open (storm) and closed (underground drainage) systems are combined into one and used in combination. In this case, the drainage contours of the pipes are located below the stormwater ones - the drainage, as it were, “cleans up” what the “stormwater” could not cope with. And their storage well or collector may well be combined.

Closed drainage system

Starting to talk about installation work When it comes to arranging a drainage system, first of all you need to say what materials will be required for this process, so that you can immediately determine the required quantity.

So, to install a closed drainage system, the following are used:

Bulk building materials - sand, crushed stone, coarse gravel or expanded clay.
Geotextiles (dornit).
Corrugated PVC pipes for installation of collector wells with a diameter of 315 or 425 mm. Wells are installed at all points of change of direction (at corners), and on straight sections - in increments of 20–30 meters. The height of the well will depend on the depth of the drainage pipes.
Perforated PVC drainage pipes with a diameter of 110 mm, as well as connecting parts to them: tees, corner fittings, couplings, adapters, etc.
Container for arranging a storage well.

The quantity of all necessary elements and materials is calculated in advance according to the drawn up design of the water drainage system.

In order not to make a mistake in choosing pipes, it is necessary to say a few words about them.

It is clear that drainage pipes are not used to drain rainwater, since through the holes water will flow under the blind area or to the foundation. Therefore, perforated pipes are installed only in closed drainage systems that drain groundwater away from the building.

In addition to PVC pipes, drainage systems are also assembled from ceramic or asbestos concrete pipes, but they do not have factory perforation, so in this case they are non-functional. You will have to drill holes in them yourself, which takes a lot of time and effort.

Corrugated perforated PVC pipes are the best option, as they are lightweight, highly flexible, and can be easily assembled into a single system. In addition, the presence of ready-made holes in the walls allows you to optimize the volume of incoming water. Except flexible pipes PVC, you can find hard versions on sale that have a smooth inner and corrugated outer surface.

PVC drainage pipes are classified according to strength level, have letter markings SN and numbers from 2 to 16. For example, SN2 products are only suitable for contours at a depth not exceeding 2 meters. At a depth of 2 to 3 meters, models marked SN4 will be required. At a depth of four meters it is better to place SN6, but SN8, if necessary, can cope with depths of up to 10 meters.

Rigid pipes are produced in lengths of 6 or 12 meters, depending on the diameter, while flexible pipes are sold in coils up to 50 meters.

Very good purchase There will be pipes on which a filter layer is already provided on top. For this purpose, geotextiles are used (more suitable for sandy soils) or coconut fibers (they show their effectiveness well on clay layers of soil). These materials reliably prevent quick creation blockages in the narrow openings of perforated pipes.

Pipe assembly in common system does not require any special tools or devices - the sections are joined manually using special couplings or fittings, depending on the model. To ensure tight connections, the products are equipped with special rubber seals.

Before moving on to the description of installation work, it is necessary to clarify that drainage pipes are always laid below the freezing depth of the soil.

Installation of a closed drainage system

When starting a description of the arrangement of the drainage system, it is necessary to mention and clearly present the fact that it can be laid not only around the house, but also throughout the entire territory of the site, if it is very wet and requires constant drying.

Prices for geotextiles

geotextiles

Installation work is carried out according to a pre-compiled project, which is developed taking into account all the parameters necessary for the normal functioning of the system.

The schematic location of the drainage pipe looks as shown in this illustration.

Illustration	Brief description of the operations performed
	The first step is to mark the passage of drainage channels on the site according to the dimensions indicated on the project. If it is necessary to drain water only from the foundation of the house, then the drainage pipe is often placed at a distance of about 1000 mm from the blind area. The width of the trench for the drainage channel should be 350÷400 mm.
	The next step, following the applied markings, is to dig trenches around the perimeter of the entire house. Their depth should also be calculated based on data obtained after soil surveys. Trenches are dug with a slope of 10 mm per linear meter of length to the side drainage well. In addition, it is good to provide small angle slope of the trench bottom from the foundation walls. Next, the bottom of the trench must be compacted well, and then laid on it sand cushion 80÷100 mm thick. The sand is spilled with water and also compacted with a manual tamper, respecting the previously formed longitudinal and transverse slopes of the trench bottom.
	As the drainage of the foundation of a built house progresses, obstacles in the form of floor slabs may arise along the path of the trench. It is impossible to leave such areas without a drainage channel, otherwise moisture, having no outlet, will accumulate in these areas. Therefore, you will need to carefully dig under the slab so that the pipe is laid continuously along the wall (so that the ring is closed).
	In addition to the remote drainage system, in some cases a wall version of the channel for water drainage is installed. It is relevant if the house has a basement or ground floor, under which an internal drainage system was not installed when the house was built. The trench is dug to a depth below the basement floor, without a large indentation from the foundation wall, which requires additional covering waterproofing material on a bitumen basis. The remaining work is similar to that which will be carried out when laying pipes running at a meter distance from the wall.
	The next step is to lay geotextiles in the trench. If the trench is deep and the width of the canvas is not enough, then it is cut and laid across the pit. The canvases are laid on top of each other with an overlap of 150 mm, and then glued together with waterproof tape. Geotextiles are temporarily secured along the upper edges of the trench with stones or other weights. When installing wall drainage, one edge of the canvas is temporarily fixed on the wall surface.
	Next, at the bottom of the trench, on top of the geotextile, a layer of sand 50 mm thick is poured, and then a layer of medium-fraction crushed stone 100 mm thick. The embankment is evenly distributed along the bottom of the trench, and care must be taken to ensure that the previously laid slope is maintained.
	In order to embed a coupling into a corrugated pipe of a plastic drainage well, the diameter is outlined on it, and then the marked area is cut out using a sharp knife. The coupling should fit tightly in the hole and protrude into the well by 120÷150 mm.
	Drainage pipes are laid on top of the embankment made in the trenches and, according to the design, inspection wells are installed, to the couplings of which pipes intersecting at a given point are attached.
	After completing the installation of pipes and wells, the design of the drainage circuit should look something like the one shown in the illustration.
	The next step is to fill the top of the drainage pipes and around the wells with coarse gravel or medium-fraction crushed stone. Embankment thickness is higher top point pipes should be from 100 mm to 250 mm.
	Next, the edges of the geotextile, fixed to the walls of the trench, are released, and then they cover the entire resulting “layered structure” from above.
	The rolled geotextile, which has completely covered the filter layer of crushed stone or gravel, is used to sand backfill, 150÷200 mm thick, which needs to be slightly compacted. This layer will become additional protection systems against soil subsidence, which is poured into the trench last top layer and is also compacted. You can do it differently: before starting to dig a trench, the turf layer is carefully removed from the ground, and after completion of the installation work, the turf is returned to its place, I green lawn again pleasing to the eye.
	When setting up a drainage system, it is necessary to remember that all the pipes that make it up must have a slope towards the inspection well, and then towards the storage well or collector, which is installed away from the house. If settling in drainage option water intake, then it is completely or its bottom part is filled with large gravel, crushed stone or broken stone.
	If you want to completely mask the covers of inspection, drainage or storage wells, you can use decorative garden elements. They can imitate a round log or a stone boulder that decorates the landscape.

Discharge of storm and melt water

Features of storm drainage

An external drainage system is sometimes called an open drainage system, meaning its purpose is to drain rainwater from the roof drain and from the surface of the site. It would probably be correct to call it a storm drain. By the way, if it is assembled according to the point principle, it can also be located hidden.

Installing such a water drainage system seems to be easier than buried drainage, since installation will require less excavation work. On the other side - important acquire elements of external design, which also requires certain costs and extra efforts.

There is another important difference. The drainage system is designed, as a rule, for constant “smooth” operation - even if problems occur. seasonal changes soil saturation with moisture, then they are not so critical. Storm sewers must be able to drain very quickly, literally within minutes, into collectors and wells large volumes water. Therefore, increased demands are placed on its performance. And this performance is ensured by correctly selected sections of pipes (or gutters - in a linear scheme) and the slope of their installation for the free flow of water.

When designing storm sewers, the territory is usually divided into water collection areas - one or more storm inlets are responsible for each area. A separate area is always the roof of a house or other buildings. They try to group the remaining parts according to similar external conditions - the external coating, since each of them is characterized by special characteristics of water absorption. Thus, it is necessary to collect 100% of the fallen volume of storm water from the roof, and from the territory - depending on the coverage of a particular area.

For each area, the average statistical water collection is calculated using the formulas - it is based on the coefficient q20, which shows the average precipitation intensity for each specific region.

Knowing the required volume of water drainage from a particular area, it is easy to determine the nominal diameter of the pipe and the required slope angle from the table.

Hydraulic cross-section of pipes or trays	DN 110	DN 150	DN 200	Slope value (%)
Volume of collected water (Qsb), liters per minute	3.9	12.2	29.8	0.3
-"-	5	15.75	38.5	0,3 - 0,5
-"-	7	22.3	54.5	0,5 - 1,0
-"-	8.7	27.3	66.7	1,0 - 1,5
-"-	10	31.5	77	1,5 - 2,0

In order not to torment the reader with formulas and calculations, we will entrust this task to a special online calculator. It is necessary to indicate the mentioned coefficient, the area of the site and the nature of its coverage. The result will be obtained in liters per second, liters per minute and cubic meters per hour.

Surface runoff is formed by rain and melt water, etc. water from road washing that flows into low areas.

The objectives of organizing surface runoff are: collection, protection and removal of water from the city territory.

Institutional drainage systems:

Open

Closed

Mixed

Most appropriate closed system drainage or storm drainage.

Based on the nature of drainage, they are divided into:

All-alloy

Separate

Semi-separated

Combined

The most developed separate system, when water from the surface is removed by an independent network.

A closed drainage network consists of elements:

Trays along the side stone PCH.

Water intake wells.

Gutter branches.

Pipeline forming a drainage network (for  more than 1.2 m - collectors)

Inspection wells.

Structures on the network (transition wells, rotary wells and chambers)

Treatment plants

Design of a closed drainage network

The drainage network is designed using a gravity system. On streets near watersheds, free flow of water is provided through street gutters to the nearest water intake well.

Watercourses are placed along the streets and, in some cases, in neighborhood areas. The longitudinal slope of the gutters is designed to be the same as the slope of the street. Drainage collectors are located below the soil freezing zone.

22. Factors influencing traffic safety, their consideration when designing highways.

The coefficient method is based on a generalization of traffic accident statistics. It is especially convenient for analyzing sections of roads that are in use and are subject to reconstruction.

A variation of this method is the sometimes used method of “relative traffic safety coefficients,” which are the inverse values of accident rates.

Characterizing the degree of traffic safety in fractional quantities makes this The method is not very intuitive.

The degree of danger of road sections is characterized by the final accident rate, which is the product of partial coefficients taking into account the influence of individual elements of the plan and profile:

Partial coefficients representing the number of incidents for a particular value of the element and profile in comparison with a reference horizontal straight section of the road with a carriageway 7 - 7.5 m wide and reinforced wide shoulders.

Intensity of traffic - width of the roadway, - width of the shoulders, - longitudinal slope

Radius of curves in plan, - visibility, - width of bridges, - length of straight sections,

Type of cross profile, - intensity at the intersection, - visibility at the intersection,

Number of traffic lanes, -building, -length of the settlement, -approaches to the settlement. point - the characteristics of the surface, - the dividing strip, - the distance to the ravine.

From Fedotov’s directory, up to 15 is normal, from 15 to 30 is repair, more than 30 is a complete redo of the road.

23. Modern methods of design and survey A.D. Automation system Design.

Computer-aided design systems for highways (CAD-AD) using a variety of automation tools and computer technology process initial information and offer ready-made complete solutions for highway design.

The design engineer, during a dialogue with the computer, analyzes design solutions and selects the best option. Composes computer programs, which are a sequence of commands written in the codes of a given computer. For getting design solutions and solutions to problems, there are application software packages.

For information support of CAD-AD, digital information about standard design solutions for the subgrade, road pavement, bridge spans and supports, pipes and road conditions is recorded on magnetic tapes or disks.

All this information is stored in the machine's memory. When designing at the CAD-AD level, the connection between the design of individual elements and the entire object as a whole must be ensured at all stages of calculation

Particularly difficult is the design of route options in plan. In order to correctly evaluate the route option, it is necessary to design all road elements, including artificial structures and longitudinal profile. If, according to some indicators, the resulting option does not suit the designer, the route plan is adjusted and the computer recalculates all elements of the road.

The screen of a cathode ray tube - display - is used to input and output information and form an image. The completed design solution is issued in the form of text, alphanumeric information or a graphic image (for example, route plan, longitudinal profile).

Plot plotters are used to display images from a computer. If necessary, the resulting image can be corrected by the designer in order to obtain a new graphic image. Plot plotters are designed to display graphic and text information on paper, tracing paper, and film with high accuracy.

Roll plotters EC-7052 and EC-7053 are used to obtain drawings of a route plan, longitudinal profile, various graphs, diagrams; tablet plotters EC-7051 and EC-7054 - for obtaining drawings of elements highway and artificial structures. One plotter can replace the work of 20-25 qualified draftsmen.

The initial information is entered into the computer memory through magnetic tape drives after deciphering the aerial photograph and determining the coordinates of the route points using a stereo model.

During ground surveys, electronic tacheometers and light rangefinders are used, recording information on magnetic tapes, which are immediately entered into a computer for further processing.

The technological line for designing a route plan has 35 application programs. At the same time, the computer processes materials from aerial surveys and ground survey results; draws up topographic plans; generates a digital terrain model; performs sketch tracing of highway options using topographic plans or stereo models; designs the route plan using the reference point method with calculation of the coordinates of the main and intermediate points; on the plotter draws the plan, longitudinal and transverse profiles of the route.

Works in this cycle include:

■ construction of upland and drainage ditches, embankment;

■ open and closed drainage;

■ surface planning of warehouse and assembly areas.

Surface and groundwater are formed from precipitation (storm and melt water). There are “foreign” surface waters, coming from elevated neighboring areas, and “our own”, formed directly on construction site. Depending on specific hydrogeological conditions production of diversion works surface waters and drainage of soils can be carried out in the following ways: open drainage, open and closed drainage and deep dewatering.

Upland and drainage ditches or embankments are installed along the boundaries of the construction site on the upland side to protect against surface water. The site area must be protected from the influx of “alien” surface water, for which purpose it is intercepted and diverted off site. To intercept water, upland and drainage ditches are installed in its elevated part (Fig. 3.5). Drainage ditches must ensure the passage of storm and melt water to low points in the area beyond the construction site.

Rice. 3.5. Protection of the construction site from the influx of surface water: 1 - water drainage zone, 2 - upland ditch; 3 - construction site

Depending on the planned water flow, drainage ditches are installed with a depth of at least 0.5 m, a width of 0.5...0.6 m, with an edge height above the design water level of at least 0.1...0.2 m. To protect the ditch tray from erosion, the speed of water movement should not exceed 0.5...0.6 m/s for sand, and -1.2...1.4 m/s for loam. The ditch is installed at a distance of at least 5 m from the permanent excavation and 3 m from the temporary one. To protect against possible siltation, the longitudinal profile of the drainage ditch is made at least 0.002. The walls and bottom of the ditch are protected with turf, stones, and fascines.

“Own” surface water is drained by giving an appropriate slope during the vertical layout of the site and installing a network of open or closed drainage, as well as by forced discharge through drainage pipelines using electric pumps.

Drainage systems open and closed types used when the site is heavily flooded with groundwater with high level horizon. Drainage systems are designed to improve general sanitary and building conditions and provide for lowering the groundwater level.

Open drainage is used in soils with a low filtration coefficient when it is necessary to lower the groundwater level to a small depth - about 0.3...0.4 m. Drainage is arranged in the form of ditches 0.5...0.7 m deep, to the bottom which a layer of coarse sand, gravel or crushed stone 10...15 cm thick is laid.

Closed drainage is usually deep trenches (Fig. 3.6) with the construction of wells for system revision and with a slope towards water discharge, filled with drainage material (crushed stone, gravel, coarse sand). The top of the drainage ditch is covered with local soil.

Rice. 3.6. Closed, wall and encircling drainage: a - general drainage solution; b - wall drainage; c - ring enclosing drainage; 1 - local soil; 2 - fine-grained sand; 3 - coarse sand; 4 - gravel; 5 - drainage perforated pipe; 6 - compacted layer of local soil; 7 - bottom of the pit; 8 - drainage slot; 9 - tubular drainage; 10 - building; 11 - retaining wall; 12 - concrete base

When installing more efficient drainages, pipes perforated in the side surfaces are laid at the bottom of such a trench - ceramic, concrete, asbestos-cement with a diameter of 125...300 mm, sometimes just trays. The pipe gaps are not sealed; the pipes are covered on top with well-draining material. Depth drainage ditch-1.5...2.0 m, top width - 0.8...1.0 m. A crushed stone base up to 0.3 m thick is often laid underneath the pipe. Recommended distribution of soil layers: 1) drainage pipe, laid in a layer of gravel; 2) a layer of coarse sand; 3) a layer of medium or fine-grained sand, all layers at least 40 cm; 4) local soil up to 30 cm thick.

Such drainages collect water from adjacent soil layers and drain water better, since the speed of water movement in the pipes is higher than in the drainage material. Closed drainages are installed below the soil freezing level; they must have a longitudinal slope of at least 0.5%. Drainage installation must be carried out before the construction of buildings and structures begins.

In recent years, pipe filters made of porous concrete and expanded clay glass have been widely used for tubular drainage. The use of pipe filters significantly reduces labor costs and the cost of work. They are pipes with a diameter of 100 and 150 mm with a large number of through holes (pores) in the wall, through which water seeps into the pipeline and is discharged. The design of the pipes allows them to be laid on a pre-leveled base using pipe layers.

The removal of surface water and lowering the groundwater level are carried out to protect construction sites and foundation pits of future structures from flooding by storm and melt water.

Work on drainage of surface and groundwater includes: construction of upland and drainage ditches, embankment; drainage device; surface layout of warehouse and assembly areas.

Ditches or trays are arranged along the boundaries of the construction site on the upland side with a longitudinal slope of at least 0.002, and their sizes and types of fastenings are taken depending on the flow of storm or melt water and limit values non-erosive speeds of their flow.

The ditch is installed at a distance of at least 5 m from the permanent excavation and 3 m from the temporary one. The walls and bottom of the ditch are protected with turf, stones, and fascines. Water from all drainage devices, reserves and cavaliers is diverted to low places, remote from constructed and existing structures.

When the site is heavily flooded with groundwater with a high horizon level, open and closed drainage systems are used.

Open drainage is used in soils with a low filtration coefficient when it is necessary to lower the groundwater level (GWL) to a depth of 0.3–0.4 m. Drainage is arranged in the form of ditches 0.5–0.7 m deep, at the bottom of which a layer of coarse-grained sand, gravel or crushed stone 10–15 cm thick.

Closed drainage is usually deep trenches with wells for system inspection and with a slope towards water discharge, filled with drained material. Sometimes pipes perforated in the side surfaces are laid at the bottom of such a trench. The top of the drainage ditch is covered with local soil.

Drainage installation must be carried out before the construction of buildings and structures begins.

Organization of drainage and artificial lowering

Groundwater level

Excavations (pits and trenches) with a small influx of groundwater are developed using open drainage.

With a significant influx of groundwater and large thickness Before the start of work, the water-saturated layer is artificially reduced.

Dewatering work depends on the method adopted mechanized development pits and trenches. Accordingly, the order of work is established both for the installation of drainage and water-reducing installations, their operation, and for the development of pits and trenches. When placing a pit on the bank within the floodplain of a river, its development begins after the installation of water-reducing equipment, so that the decrease in groundwater level is ahead of the deepening of the pit by 1–1.5 m. If the pit is located directly in the riverbed, then before dewatering work it is fenced off on the water side with special dams (lintels). Drainage work consists of removing water from the fenced-off pit and then pumping out the water that filters into the pit.

In the process of draining a pit, it is important to choose the correct pumping speed of water, since very rapid drainage can cause damage to the lintels, slopes and bottom of the pit. In the first days of pumping, the intensity of the decrease in water level in pits from coarse-grained and rocky soils should not exceed 0.5–0.7 m/day, from medium-grained soils - 0.3–0.4 m/day and in pits from fine-grained soils 0. 15–0.2 m/day. In the future, water pumping can be increased to 1–1.5 m/day, but in the last 1.2–2 m of depth, water pumping should be slowed down.

In an open drainage pumping of incoming water directly from the pit or trenches is provided. It is applicable in soils that are resistant to filtration deformations (rock, gravel, etc.). With open drainage, groundwater, seeping through the slopes and the bottom of the pit, enters drainage ditches and through them into pits (sumps), from where it is pumped out. The dimensions of the pits in plan are 1×1 or 1.5×1.5 m, and the depth is from 2 to 5 m, depending on the required immersion depth of the pump’s water intake hose. Minimum dimensions The pit is prescribed to ensure continuous operation of the pump for 10 minutes. Pits in stable soils are secured wooden log house from logs (without bottom), and in floating ones - sheet pile wall and a return filter is installed at the bottom. Trenches are secured in approximately the same way in unstable soils. The number of pits depends on the estimated water flow to the pit and the performance of the pumping equipment.

The influx of water to the pit (or flow rate) is calculated using the formulas for the steady-state movement of groundwater. Based on the data obtained, the type and brand of pumps and their number are specified.

Open drainage is an effective and simple method of drainage. However, it is possible that the soil at the base may loosen or liquefy and some of the soil may be carried away by filtered water.

Artificial decrease in groundwater level involves the construction of a drainage system, tube wells, wells, and the use of wellpoints located in close proximity to the future pit or trench. At the same time, the groundwater level sharply decreases, the previously water-saturated soil and now dehydrated soil is developed as soil of natural moisture.

There are the following methods of artificial water reduction: wellpoint, vacuum and electroosmotic.

Artificial water reduction methods eliminate water seepage through the slopes and the bottom of the pit, so the slopes of the excavations are preserved intact, and there is no removal of soil particles from under the foundations of nearby buildings.

The choice of water reduction method and the type of equipment used depends on the depth of the excavation pit (trench), engineering-geological and hydrogeological conditions of the site, construction time, structure design and TEP.

Artificial water reduction is carried out when the drained rocks have sufficient water permeability, characterized by filtration coefficients of more than 1–2 m/day; it cannot be used in soils with a lower filtration coefficient due to the low speeds of groundwater movement. In these cases, evacuation or electrodehumidification (electro-osmosis) is used.

Wellpoint method provides for the use of frequently located wells with tubular water intakes of small diameter for pumping water from the ground - wellpoint filters, connected by a common suction manifold to a common (for a group of wellpoints) pumping station. To artificially lower the groundwater level to a depth of 4–5 m in sandy soils, use light wellpoint units (LIU). To drain trenches up to 4.5 m wide, single-row wellpoint units are used (Fig. 2.1, A), with wider trenches - double-row (Fig. 2.1, b).

To drain pits, closed-circuit installations are used. When the hydrocarbons are reduced to a depth of more than 5 m, two- and three-tier wellpoint installations are used (Fig. 2.2).

In the case of using two-tier wellpoint installations, the first (upper) tier of wellpoints is first put into operation and, under its protection, the upper ledge of the pit is torn off, then the second (lower) tier of wellpoints is mounted and the second ledge of the pit is torn off, etc. After each subsequent tier of wellpoints is put into operation, the previous ones can be turned off and dismantled.

The use of wellpoints is also effective for reducing water in low-permeability soils, when a more permeable layer lies underneath them. In this case, wellpoints are buried in the lower layer with obligatory sprinkling.

Rice. 2.1. Water reduction with light wellpoint systems: A– one-

in-line wellpoint units; b– double-row wellpoint units;

1 – trench with fastening; 2 - hose; 3 – valve; 4 – pumping unit;

5 – suction manifold; 6 – wellpoints; 7 – reduced groundwater level;

8 – water intake filter unit of the wellpoint

Rice. 2.2. Scheme of tiered water reduction of needle filters

trami: 1 , 2 – respectively, wellpoint filters of the upper and

lower tier; 3 – final decrease in depression

groundwater surface

In addition to wellpoints, the LIS also includes a water collection collector that combines the wellpoints into one water-reducing system, centrifugal pumping units and an outlet pipeline.

To lower the wellpoint into the working position in difficult soils, drilling wells into which the wellpoints are lowered is used (at depths of up to 6–9 m).

In sand and sandy loam soils, wellpoints are immersed hydraulically, by washing the soil under the milling tip with water at a pressure of up to 0.3 MPa. After the wellpoint is immersed to the working depth, the hollow space around the pipe is partially filled with subsided soil, and partially filled with coarse sand or gravel.

The distances between wellpoints are taken depending on their arrangement, the depth of water drawdown, the type of pumping unit and hydrogeological conditions, but usually these distances are 0.75; 1.5 and sometimes 3 m.

Vacuum method Water reduction is based on the use of ejector water reduction units (EIU), which pump water from wells using water-jet ejector pumps. These installations are used to reduce groundwater level in fine-grained soils with a filtration coefficient of 0.02–1 m/day. The depth of the groundwater level depression in one tier ranges from 8 to 20 m.

EIUs consist of wellpoints with ejector water lifts, a distribution pipeline (collector) and centrifugal pumps. Ejector water receivers placed inside the wellpoints are driven by a jet of working water pumped into them by a pump under a pressure of 0.6–1.0 MPa through the manifold.

Ejector wellpoint filters are immersed hydraulically. The distance between wellpoints is determined by calculation, but on average it is 5–15 m. The choice of wellpoint equipment, as well as the type and number of pumping units, is made depending on the magnitude of the expected groundwater influx and the requirements for limiting the length of the collector served by one pump.

Electroosmotic water reduction, or electrodehumidification, is based on the phenomenon of electroosmosis. It is used in low-permeability soils with a filtration coefficient Kf of less than 0.05 m/day.

First, along the perimeter of the pit (Fig. 2.3) at a distance of 1.5 m from its edge and in increments of 0.75–1.5 m, wellpoint cathodes are immersed, on the inside of the contour of these wellpoints at a distance of 0.8 m from them with such In the same step, but in a checkerboard pattern, steel pipes (anode rods) connected to the positive pole are immersed, wellpoints and pipes are immersed 3 m below the required water reduction level. When skipping direct current water contained in the pores of the soil moves from the anode to the cathode, and the soil filtration coefficient increases by 5–25 times. Pits usually begin to be excavated three days after the electric drainage system is turned on, and later work in the pit can be carried out with the system turned on.

Open (connecting to the atmosphere) water-reducing wells used for large depths of groundwater level depression, as well as

when the use of wellpoints is difficult due to large inflows and the need for drying large areas and tightness of the territory. For pumping water from wells, artesian turbine pumps of the ATN type are used, as well as deep well pumps submersible type.

Rice. 2.3. Scheme of electrical soil drainage:

1 – anode pipes; 2 – wellpoint cathodes;

3 – pumping unit; 4 – reduced groundwater level

The use of methods for reducing groundwater level depends on the thickness of the aquifer, soil filtration coefficient, parameters earthen structure and construction site, method of work.

Discharge of surface and ground water.

Works in this cycle include:

■ construction of upland and drainage ditches, embankment;

■ open and closed drainage;

■ surface planning of warehouse and assembly areas.

Surface and groundwater are formed from precipitation (storm and melt water). There are “foreign” surface waters, coming from elevated neighboring areas, and “our own”, formed directly at the construction site. Depending on the specific hydrogeological conditions, work on the drainage of surface water and soil drainage can be carried out in the following ways: open drainage, open and closed drainage and deep dewatering.

Rice. 3.5. Protection of the construction site from the influx of surface water: 1 - water drainage zone, 2 - upland ditch; 3 - construction site

Drainage systems of open and closed types are used when the site is heavily flooded with groundwater with a high horizon level. Drainage systems are designed to improve general sanitary and building conditions and provide for lowering the groundwater level.

When installing more efficient drainages, pipes perforated in the side surfaces are laid at the bottom of such a trench - ceramic, concrete, asbestos-cement with a diameter of 125...300 mm, sometimes just trays. The pipe gaps are not sealed; the pipes are covered on top with well-draining material. The depth of the drainage ditch is 1.5...2.0 m, the width at the top is 0.8...1.0 m. A crushed stone base up to 0.3 m thick is often laid underneath the pipe. Recommended distribution of soil layers: 1) drainage pipe laid in a layer of gravel; 2) a layer of coarse sand; 3) a layer of medium or fine-grained sand, all layers at least 40 cm; 4) local soil up to 30 cm thick.

Engineering preparation of the construction site.

General provisions

Any construction (facility or complex) is preceded by site preparation aimed at ensuring necessary conditions high-quality and timely construction of buildings and structures, including engineering training and engineering support.

During engineering training, a set of processes (works) is performed, in general the most characteristic of which in technology construction production are the creation of a geodetic alignment base, clearing and planning of the territory, drainage of surface and pound water.

In each specific case, the composition of these processes and the methods of their implementation are regulated by natural and climatic conditions, the characteristics of the construction site, the specifics of the buildings and structures being erected, the characteristics of the facility - new construction, expansion or reconstruction, etc.

Engineering support for the construction site provides for the installation of temporary buildings, roads and water and electricity supply networks, etc. The construction site is equipped with changing rooms, a canteen, a workman's office, showers, bathrooms, and storage warehouses building materials, tools, temporary workshops, sheds, etc. It is advisable to use part of the demolished buildings for these structures, if they do not fall within the dimensions of the structure being erected and will not interfere with the normal implementation of construction work, as well as inventory buildings of carriage or block type.

To transport goods, the existing road network should be used as much as possible and temporary roads should be installed only if necessary.

During the preparatory period, temporary water supply lines are laid, including fire-fighting water supply, and electricity supply with energy supply to all cabins and places where electrical mechanisms are installed. The foreman's room must be provided with telephone and dispatch communications. A place for repairs and parking of earth-moving and other machines and vehicles will be equipped at the construction site. The site must be fenced or marked with appropriate signs and inscriptions.

Creating a geodetic alignment base

At the stage of site preparation for construction, a geodetic alignment base must be created, which serves for planning and elevation justification when the project of buildings and structures to be erected is taken to the area, as well as (subsequently) for geodetic support at all stages of construction and after its completion.

A geodetic alignment basis for determining the position of construction objects in the plan is created mainly in the form of: construction mesh, longitudinal and transverse axes that determine the location on the ground of the main buildings and structures and their dimensions, for the construction of enterprises and groups of buildings and structures; red lines (or other development control lines), longitudinal and transverse axes that determine the location on the ground and the dimensions of the building, for the construction of individual buildings in cities and towns.

The construction grid is made in the form of squares and rectangles, which are divided into main and additional (Fig. 1, a). The length of the sides of the main grid figures is 100... 200 m, and the additional ones - 20... 40 m.

Rice. 1 - Construction grid: a - location of grid points; b - removal of the construction grid to the area; 1- vertices of the main mesh shapes; 2 - main axes of the building; 3 - vertices of additional mesh figures

When designing a construction grid, the following must be ensured: maximum convenience is provided for performing marking work; main ones being built

buildings and structures are located inside grid figures; the grid lines are located parallel to the main axes of the buildings being constructed and as close to them as possible; direct linear measurements.

Rice. 2 - Permanent geodetic signs: a - from concreted pipe scraps; b - from a steel pin with a concreted head; c - from scraps of rails; 1 - planned point; 2 - steel pipe with a cross-shaped anchor, 3 - concrete head; 4 - steel pipe; 5 - freezing limit

The breakdown of the construction grid on the ground begins with the outlining of the original direction, for which they use the geodetic network available on the site (or near it) (Fig. 1, b). Using the coordinates of geodetic points and grid points, the polar coordinates S1, S2, S3 and angles are determined, along which the original directions of the grid (AB and AC) are placed on the terrain. Then, starting from the initial directions, a construction grid is broken out across the entire site and secured at the intersections with permanent signs (Fig. 2) with the planning point. Signs are made from concreted scraps of pipes, rails, etc. The base of the sign (bottom of the sign, sign support) must be located at least 1 m below the freezing line of the soil.

The red line is moved and secured in the same way.

When transferring the main axes of objects under construction to the terrain, if there is a construction grid as a planned alignment basis, the method of rectangular coordinates is used. In this case, the nearby sides of the construction grid are taken as coordinate lines, and their intersection is taken as the reference zero. The position of point O of the main axes xo - yo will be determined as follows: if it is given that xo = 50 and yo = 40 m, then this means that it is located at a distance of 50 m from the line x towards xo and at a distance of 40 m from line y towards line oo.

If there is a red line as a planned alignment basis, the construction plan must contain some data defining the position of the future building, the angle between the main axis of the building and the red line and the distance from point A to point O of the intersection of the main axes.

The main axes of the building are fixed behind its contours with the signs of the above design.

High-altitude justification at the construction site is provided by high-altitude support points - construction benchmarks. Typically, reference points of the construction grid and red line are used as construction reference points. The elevation of each construction benchmark must be obtained from at least two benchmarks of the state or local geodetic network.

During the construction process, it is necessary to monitor the safety and stability of the signs of the geodetic alignment base, which is carried out by the construction organization.

Clearing the area

When clearing the territory, green spaces are replanted if they are used in the future, they are protected from damage, stumps are uprooted, the site is cleared of bushes, the fertile layer of soil is removed, unnecessary buildings are demolished or dismantled, underground communications are rebuilt and, finally, the construction site is laid out.

Green spaces that are not subject to cutting down or replanting are surrounded by a fence, and the trunks are separated standing trees protect from possible damage, protecting with lumber waste. Trees and shrubs suitable for later landscaping are dug up and transplanted to a protected zone or to a new location.

Trees are felled using mechanical or electric saws. Tractors with skidding-rooting winches or bulldozers with high-raised blades cut down trees with roots and uproot stumps. Individual stumps that cannot be uprooted are split by explosion. Brush cutters are used to clear the area of bushes. For the same operation, bulldozers with ripper teeth on the blade and uprooters-collectors are used. The hedge trimmer is a replacement piece of equipment for a crawler tractor.

The fertile layer of soil to be removed from built-up areas is cut off and moved to specially designated areas, where it is stored for later use. Sometimes it is taken to other sites for landscaping. When working with fertile layer it should be protected from mixing with the underlying layer, contamination, erosion and weathering.

Demolition of buildings and structures is carried out by dividing them into parts (for subsequent dismantling) or collapsing. Wooden buildings disassembled, rejecting elements for their subsequent use. When disassembling, each detachable prefabricated element must first be unfastened and occupy a stable position.

Monolithic reinforced concrete and metal buildings are dismantled according to a specially designed demolition scheme that ensures the stability of the structure as a whole. Division into disassembly blocks begins with opening the reinforcement. Then the block is secured, after which the reinforcement is cut and the block is broken off. Metal elements are cut off after unfastening. The largest mass of a reinforced concrete dismantling block or metal element should not exceed half the lifting capacity of the cranes at the maximum hook reach.

Prefabricated reinforced concrete buildings are dismantled according to the demolition scheme, the reverse of the installation scheme. Before disassembly begins, the element is freed from its bonds. Prefabricated reinforced concrete structures, which cannot be separated element by element, are dissected as monolithic.

The demolition of buildings and structures by collapse is carried out with hydraulic hammers, jackhammers, and in some cases - with excavators with various attachments - balls, wedge hammers, etc. Vertical parts of the structure should be collapsed inward to prevent the scattering of debris over the area. Collapse is also carried out using explosive methods.

After clearing, a general layout of the construction site is carried out.